The questions asked in this proposal represent a new way of thinking about motor transitions in infancy. Rather than focusing on how infants navigate the complicated physical tasks inherent to beginning to reach, these experiments explore why they do so: what entices infants to act on objects in the first place? I examine three possible sources of motivation: Object-driven, Other-driven, and Self-driven. Experiments investigate the influence of all three sources and go on to further investigate the role of self-driven factors, hypothesizing that feedback from infants'own actions on objects (first those produced accidentally, later those produced intentionally) is critically important for making the transition into reaching at the appropriate time. This feedback is reinforcing and helps draw infants into more interactions with objects. Testing this model involves the use of sticky mittens, a device invented by the P.I. to study the transition into reaching during infancy. Overall, this proposal breaks new ground in motor development research and offers a new lens through which researchers can understand motor transitions in infancy. It also will provide clear-cut plans for interventions that could help infants with visual or motor impairments begin reaching for objects earlier than they would otherwise. PUBLIC HEALTH RELEVANCE: The proposed research investigates the question of why infants begin reaching for objects by testing three possible ideas: infants are curious about objects, they want to imitate other people, and/or they learn from the consequences of their own actions. If we understand what motivates typically developing infants to reach for objects, we can design interventions to help atypically developing infants begin to reach earlier than they would otherwise. The earlier infants become interested in and begin reaching for objects on their own, the more they can learn about the physical world.